The invention relates to devices for selectively allowing and preventing passage of a fluent material from a container. Various devices have been provided for closing containers of fluent material and selectively allowing passage of the fluent material out of the container, one such device being shown in U.S. Pat. No. 3,181,743. Such devices have not been wholly satisfactory, at least in part because of reliance on deforming a molded dispensing spout in the sealed position, which is undesirable because the material is prone to taking a permanent set when stored in a sealed position for long periods.
U.S. Pat. No. 3,323,694 to Stevens relates to a closure mechanism which utilizes a spout which is inverted to maximize the use of available space in shipping cartons. A disadvantage of structures of this type is that they are not adapted to seal without the use of an additional cap or plug, the structures not sealing on inverting.
U.S. Pat. No. 2,893,613 to Akers shows a closure mechanism wherein a spout which is allowed to flex closed by a diaphragm comprising a depressed shallow portion, an upstanding wall, two side walls and a top wall section. In flexing closed, the depressed shallow portion and the upstanding wall move in an over-center toggle manner. However, no provision is made to allow the side walls or top wall section to move in an over center toggle manner, thus causing these sections to buckle and bend in a random manner which tends to force the spout to an upward or dispensing position. The integrity of this type of device is very poor and the life of its diaphragm is very limited.
Other closure devices utilize rigid structures which are separately molded and then assembled with a spout positioned in aligned relationship with an opening and a base to allow passage of fluent material. Such structures are relatively expensive to manufacture.
A major disadvantage of one piece closures that utilize a hinged cap molded in dispensing position (180 degrees from the face of the cap) is that a larger and less efficient molding machine is required, in order to provide double cavity area and clamp tonage.
An object of the invention is the provision of a dispensing closure and valve which overcomes the foregoing disadvantages and shortcomings.
An object of the invention to provide a device which is quick and convenient to operate.
An object of the invention is to provide a durable device which will continue to function satisfactorily even after many openings and closings.
It is an object of the invention to provide a device which will not take a set and will continue to function satisfactorily after long periods of storage.
Another object of the invention is to provide a device which will not leak under conditions which would cause prior sealing structures to leak.
Another object of the invention is to provide a device which may be molded and closed in one operation in the molding process without requiring any additional equipment or operation to close or assemble the closure.
Another object of the invention is to provide a device which will be relatively free of clogging by material accumulating in the spout and solidifying.
Another object of the invention is to provide a device which can be manufactured using known mass production techniques.
Another object of the invention is to provide a device which is less expensive than other devices which provide capabilities which are at all comparable.